Ferrous metal



Nov. 30, 1937. M. J. CONWAY FERROUS METAL Filed Aug. 26, 1935 IINVENTOR:

WITNESJEJ ATTORNEY-3'.

Patented Nov. 30, 1937 UNITED STATES PATENT OFFICE.

muons METAL Martin J. Conway, Coatesville, Pa. Application Augus't 26,1935, Serial No. 37,811

13 Claims.

or their mixtures, products resembling wrought iron in structure but ofsuperior corrosion resistance as contrasted with ordinary wrought iron.

Still another object is to utilize iron and steel scrap to providearticles somewhat similar structurally to wrought iron but havingenhanced corrosion resistance as contrasted with ordinary Wrought iron.

A further object is to convert bundled scrap steel or iron, either orboth, by direct operations, and without remelting, into useful articleshaving superior corrosion resistance as contrasted with the originalbundled material.

Another object is to apply wrought iron fagoting practice to theproduction of articles of steel or iron, or their mixtures,'characterized by possessing mechanical properties adequate to theirintended purpose and having substantial corrosion resistance. I

The invention maybe described in connection with the accompanyingdrawing in which Fig. 1 is a schematic perspective view showing a bundleof steel scrap for use in the practice of the inven tion; Fig. 2 aperspective view illustrating schematically the macrostructure of asteel bar produced by the practice of the invention from the bundleshown in Fig. 1; Fig. 3 a perspective view of a fagot or pile made inaccordance with the invention from bar steel; and Fig.4 a schematicperspective view showing the application of the invention to powderediron.

The invention is applicable to steel, either of the plain carbon*variety or of the alloy type, such as, for example, steels containing,singly or in combination, chromium, tungsten, manganese, silicon,nickel, cobalt, copper, vanadium, molybdenum, titanium, and otheralloying elements. It is applicable likewise to the treatment of iron,whether plain or alloyed, and also to.the treatment of mixtures of steeland iron or wrought iron. Since the invention is directly applicable toall these materials it will be understood that for brevity of referencein generalized discussion of the invention reference may be made to theindividual materials but that such reference equally contemplates theother materials referred to.

This invention applies to the making of metallic articles by hot workingmasses composed of individual pieces of the solid metals referred t6, 5i. e., without remelting them. In accordance with the invention thepieces of metal, whether iron or steel, or mixtures thereof, are treatedbefore hot working to provide the surfaces with a coating comprising anoxide adapted to increase the corrosion resistance of the finishedarticle as contrasted with an article made similarly without the use ofsuch an oxide. The oxide is selected and used in an amount such as toprovide the desired corrosion resistance. The thus coat- 1 ed materialin the form of compact masses, e g., compressed bundled scrap, is thenhot worked, as by rolling, pressing, forging, or similar operations, tocause consolidation, or welding, of the individual pieces with formationof an integral product in which the oxide remains preponderantly as suchdistributed throughout its structure. In other words, the solid metalpieces are caused to coalesce by hot working, the oxide applied prior toworking to the metal surfaces being retained in and-disseminated throughthe structure of the finished article.

In this manner there are produced articles having superior corrosionresistance as contrasted with articles either made in the same way butwithout the use of such oxide, or made by processes in which such oxideis wholly or for the most part reduced withformation of an alloy of theferrous base and the metal liberated from the oxide. The article thusproduced may then be subjected to any necessary fabricating operations,the-practice of the invention not substantially interfering withcustomary practice in such operations.- I

Various oxides adapted to reduce corrosion of 'iron and steel may beused in the practice of the invention. Chromium oxide is the preferredexample. There mayalso be used other oxides adapted to confer improvedcorrosion-resisting properties when used in the manner described herein,examples beingnickel oxide, titanium oxide, vanadium oxide, and cobaltoxide. If desired there may be used mixtures of these oxides.

Insome instances the properties of-the resultant article may be variedby using-a mixture of one or more such oxides and another substance,-slags, slag-forming oxides, silica, and slag-far n ing compositionsbeing examples of the latter materials. Thus, silica may be mixed withthe corrosion-repressing oxide, or there may be used iron silicateslags, or substances productive thereof under operating conditions, andother slag and slag-like materials. As to slag materials I prefer thosewhich form slags of glass-like nature. v

A major embodiment of the invention contemplates its application toscrap metal,.particularly sheet scrap. In this aspect of the inventionthe metal is compressed into bundles,"such as those in which scrap-metalis commonly marketed, to prepare it for hot working. The oxide may beapplied to the surfaces of the metal according to a variety ofprocedures which will suggest themselves. Chief among these areimmersion of the metal in an aqueous or other suspension of the oxide,or spraying the metal with a suitable oxide suspension in a liquidmedium, or with the dry powdered oxide. The chief criterion is that theoxide shall be uniformly distributed throughout the bundle and over thesurfaces of the solid metal. If desirable there may be added to the"coating material a temporary binder to maintain adherence to the oxideupon the surfaces until subsequent hot working hasconsolidated thematerial.

The metal may be coated either before or after it has been bundled.Where the bundle has not been compacted suiliciently to prevent entryand distribution of the coating material it is preferred to coat themetal in bundled form because the bundling of previously coated metalmay tend to cause the oxide coating to become dislodged to a greater orlesser extent. Thecoated bundle is then compressed to densify it as faras possible,

to minimize oxdiation during subsequent heating and to simplify hotworking. It is then heated and welded by application of pressure,'e. g.by rolling, forging, or simple pressing. This pro- 'duces an integralwelded structure in which the coating material cooperates to producea'structure resembling that of wrought iron. The article may be broughtto finished form by such an operation, or there may be produced billetsand the like for subsequent fabricating operations.

A particular feature of the present invention resides in the utilizationof tinned steel scrap, of which large quantities are available. practiceof the invention the scrap is detinned according to any suitableprocedure, and the detinned steel scrap is then compressed to producebundles of conventional form, illustrated schematically in Fig. 1. Thebundle is then treated as described above to provide it with, forinstance, a coating of chromic oxide and silica distributed as uniformlyas possible over the surfaces of the entire bundle and in an amountadapted to provide the desired corrosion resistance in the ultimatearticle. The bundle is then compressed, as in an hydraulic press, andthe compressed mass is heated to a welding temperature and hot worked toeffect welding and produce a solid integrally united article orbillethaving the oxide distributed throughout its structure andpreponderantly remaining in its oxide form.

I Fig. 2 represents schematically the macrostructure of a bar rolledfrom the bundle shown in Fig. 1 and treated as just described. Thestructure comprises steel grains I between which there are distributedstringers or lamella 2 of the oxide applied to the starting material.Where slag has been added, or slag-like or slag-forming constituents,stringers 2 will, of course, consist of slag. It will be observed thatthis structure is similar to that which characterizes' wrought iron."The-product, however,

enhanced corro- In thesion resistance as contrasted with an article madefrom the same material and in the same manner but without the use ofoxide which characterizes the present invention.

The invention is applicable also to the production ofarticles'characterized by improved corrosion resistance from bar and thelike stock, instead of bundled scrap, in the manner applied in wroughtiron fagoting practice. This aspect of the invention is illustrated inFig. 3 which shows a fagot or pile formed from a. plurality of steelbars 3. The contiguous surfaces of the bars are provided with a coating4 of oxide of the class referred to hereinabove. The resulting pile orfagot is heated to welding temperature and rolled in accordance withcustomary practice to cause the bars to weld together in'to'an integralmass the structure of which will resemble thatshown inFig. 2.

Similarly, steel sheet scrap, such as detinned scrap, may be bundled,compressed, heated to welding temperature to produce bars which are thenassembled into piles and rolled as just described.

The invention is applicable, furthermore, to the production of articlesby pressing iron powder, a variety of procedures of this general typebeing known to the art. This embodiment is illustrated schematically inFig. 4 which shows a billet formed by compression of iron powder. In thepractice of the present invention as applied to such a procedure theparticles of iron prior to compression to form the billet are providedwith a coating of the oxide of the class contemplated by the presentinvention. The billet having been formed it is then treated under heatand pressure in accordance with the particular procedure being followed,the result being again an article having the oxide, slag formed from it,or a mixture of the oxide and slag distributed throughout its structureas described hereinabove.

The properties of the article made in accordance with the invention may,of course, be varied by a suitable selection of the starting material.

Thus, certain properties are to be obtained by the use of straight steelmaterial, such as low carbon detinned steel scrap, while otherproperties may be obtained through the use of alloy steel, or bymixtures of plain carbon and alloy steel. Other mechanical propertiesmay be had by the use of iron, and stfll further variations areobtainable through the use of combinations of throughout the metalstructure. Hence reference herein and in the appended claims toretention of the oxide in the finished artlcle' means that I for themost part it is not reduced to free its metallic'constituent. It will beunderstood, however, from what has been said hereinabove, that since theoxide may unite with other oxides or slag-forming materials to formcomplex oxides or slags, this is within the contemplation of theinvention because such combinations without reduction of the oxide toliberate the metallic constituent cause retention of the oxide withinthe contemplation of the invention.

The criterion as to the amount of oxide incorporated in the metal isthat enough is used to produce the desired degree of corrosionresistance. Clearly the exact amounts will depend upon the compositionof the metal used, upon the oxide used, upon the condition in which thearticle is used, upon the character of corroding media encountered, andperhaps upon other factors, so that exact values for the oxides suitedto all conditions can not be given. However, for many purposes it ispreferred to use chromium oxide or cobalt oxide in an amount equivalentto from 0.1 to 2 per cent of chromium or nickel, as the case may be, inthe finished article; vanadium and titanium oxides in amountscorresponding to about 0.15 to 3 per cent of vanadium or titanium in thefinished article; and nickel oxide equivalent to about 0.2 to 4 per centof nickel in the finished article. 1

According to the provisions of the patent statutes, I have explained theprinciple of my invention and have illustrated and described what I nowconsider to represent its best embodiment. However, I desire to have itunderstood that, within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically illustrated anddescribed.

I claim:

1. That method of making ferrous metal articles which includes preparinga bundle of steel scrap, applying to the surfaces of the scrap a coatingcomprising (1) an oxide adapted to confer corrosion resistance on thefinished article, and (2) material of the group silica, silicate slag,and materials productive of silicate slag, and hot working the bundleheated to a welding temperature and thereby consolidating it into anintegrally welded and mechanically strong article .having said oxidepreponderantly retained therein and distributed therethrough and imparting corrosion resistance to the article, the

artlclehaving a wrought iron-like structure.

2. That method of making ferrous metal articles which comprises applyingto the surfaces of steel barsva coating comprising an oxide adapted toconfer corrosion resistance on the finished article, forming a pile fromthe coated bars, heating the pile to a welding temperature, and hotworking the heated pile to cause welding and form an article having saidoxide preponderantly retained therein and uniformly distributedtherethrough in an amount imparting corrosion resistance to the article,the article having a wrought iron-like structure.

a 3. That method of making ferrous metal articles which comprisesapplying to the surfaces of steel bars a coating comprising acorrosion-repressing oxide of the group chromium, nickel,

vanadium, titanium, cobalt, forming a pile from the coated bars, and hotworking the pile heated to a welding temperature to cause welding andform an article having said. oxide preponderantly retained therein anduniformly distributed therethrough and imparting corrosion resistance tothe article, said oxide being present in an amount equivalent to about0.1 to 4 per cent N of the metal of such oxide. the article having awrought iron-like structure.

4. That'method of making ferrous-metal articles which includes the stepsof applying to the surfaces of solid steel, iron, or steel and ironmaterial, a coating comprising an oxide adapted to confer corrosionresistance on the finished article, and hot working at a weldingtemperature a mass composed of a plurality of pieces of such coatedmaterial and integrally welding said pieces into a consolidated, unitaryand mechanically strong article having said oxide retained therein as awrought iron-like structure and in an amount imparting corrosionresistance to the article.

5. That method of making ferrous metal articles which includes the stepsof applying to the surfaces of solid steel, iron, or steel andironmaterial, a coating comprising a corrosion-repressing oxide of the groupchromium, nickel, vanadium, titanium, cobalt, and hot working at awelding temperature a mass composed of a pinrality of pieces of suchcoated material and integrally welding said pieces into a consolidated,

-unitary and mechanically strong article having said oxidepreponderantly retained therein as a wrought iron-like structure, saidoxide being present in the finished article in an amount equivalent toabout 0.1 to 4 per cent of the metal of such oxide. v

6. That method of making ferrous metal articles which includes the stepsof applying to the surfaces of solid steel, iron, or steel and ironmaterial, a coating comprising silica and a corro-- sion-represslngoxide of the group chromium, nickel, vanadium, titanium, cobalt, and hotworking at a welding temperature amass composed .of a plurality ofpieces of such coated material cobalt, and applying pressure to a masscomposed of a plurality of pieces of such coated material, the massbeing heated to a welding temperature, and thereby integrally weldingsaid pieces into a consolidated, unitary and mechanically strong articlehaving said oxide preponderantlyretalned therein as a wrought iron-likestructure and in an amount imparting corrosion resistance to thearticle.

8. That method of making ferrous metal articles which includes the stepsof' applying to the surfaces of iron powder a coating comprising anoxide adapted to confercorrosion resistance on the finished article,compressing the coated powder to form a billet, and hot working thebillet heated to a welding temperature and the billet at a weldingtemperature and thereby consolidating it into an integrally welded andmechanically strong article having said oxide preponderantly retainedtherein and uniformly distributed therethrough and imparting corrosionresistance to the article, said oxide being present in an amountequivalent to about 0.1 to 4 per cent of the metal of such oxide, thearticle having a wrought iron-like structure.

10. That method of making ferrous metal articles which comprisespreparing a bundle of steel scrap, applying to the surfaces of the scrapin the bundle a coating comprising an oxide adapted to confer corrosionresistance on the finished article, heating the bundle to a weldingtemperature, and hot working the thus heated and coated bundle andthereby consolidating it into an integrally welded and mechanicallystrong article having said oxide preponderantly retained therein anduniformly distributed therethrough and imparting corrosion resistance tothe. article, said oxide being present in an amount equivalent to about0.1 to 4 per cent of the metal of such oxide, the article having awrought iron-like structure.

11. That method of making ferrous metal articles which includespreparing 'a bundle of steel scrap, applying to the suri'aca of thescrap in the bundle a coating comprising (1') a material of the groupsilica, silicate slag, and substances productive of silicate slag, and(2) a corrosion-repressing oxide of the group chromium, nickel,vanadium, titanium, and cobalt, and hot working the coated bundle heatedto a welding temperature and thereby consolidating it into an integrallywelded and mechanically strong article having said oxide preponderantlyretained therein and uniformly distributed therethrough and impartingcorrosion resistance to the article, the articlehaving a wroughtiron-like 5 structure. I.

12. That method of making ferrous metal articles which comprisespreparing a bundle of alloy steel scrap, applying to the surfaces of thescrap in the bundle a coating comprising a corrosion-repressing oxide ofthe group chromium, nickel, vanadium, titanium, and cobalt, compressingthe bundle under high pressure, and hot working the bundle heated to awelding temperature to weld it into an article having said oxidepreponderantly retained therein and uniformly distributed therethroughand imparting corrosion resistance to the article, the article having awrought iron-like structure.

7 13. That method. of making ferrous metal 20 articles comprising thesteps of bundling and compressing steel scrap, hot working said bundleto form a steel bar, coating the surfaces of a plurality of said barswith a corrosion-repressing oxide of the group chromium, nickel,vanadium, titanium and cobalt, forming a pile or fagot from such coatedbars, heating the pile to a'welding temperature and hot working it andthereby welding said bars into an integrally welded and mechanicallystrong article having said oxide preponderantly retained therein anddistributed therethrough' and imparting corrosion resistance to thearticle, the article having a wrought ironlike structure.

MARTIN .1. conwn

